Fractured ulna Coronoid fracture 2024-12-03T17:26:54Z The coronoid process acts to buttress against the posterior translation of the ulna on the humerus. It is also the attachment site for the anterior elbow capsule, brachialis, and the medial collateral ligament of the elbow. Coronoid fractures are critical injuries and are suggestive of elbow instability. Fracture of the coronoid process on the proximal ulna.